Eli Manning fumbles as he is hit by New Orleans Saints defensive end Will Smith in the Giants' 49-24 loss yesterday. Photo: AP

New York Giants players watch late in the fourth quarter of last night’s loss to the Saints. (Reuters)

NEW ORLEANS — They are the words no one around the Giants wants to hear.

Collapse. Swoon. Meltdown.

Take your pick.

Tom Coughlin and Eli Manning knew their history together long before they and the Giants came marching in to the Superdome last night and went marching out disgraceful 49-24 losers.

Mardi Blah.

Two years ago, Drew Brees torched the Giants for 369 yards and four touchdowns in a 48-27 rout.

Now this: 363 yards, four TD passes, a pair to freakish TE Jimmy Graham, and a rushing touchdown. The second worst defensive performance (577 yards) in franchise history.

Deja Drew.

This was men against boys.

A carefree night at Café du Monde, Brees all but taking a few bites of a beignet, then making the best possible decision and best possible throw.

A legitimate Super Bowl contender schooling a Super Bowl pretender.

Those who cannot remember the past are condemned to repeat it, remember.

Manning and Coughlin, who uncharacteristically lost a pair of coach’s challenges in the second half, have remembered their past and haven’t been able to do much about it.

A fast start.

A spineless finish.

Now this.

“I know what you guys are gonna say next week . . . I know what everybody’s gonna write about,” Justin Tuck said. “I know everybody knows what they’re gonna write about, like you just asked me, three straight losses . . . so, we can’t fall into that trap thinking that somebody’s gonna feel sorry for us. We gotta go out there and win a football game.”

Manning doesn’t have a running game without Ahmad Bradshaw, and Coughlin doesn’t have a big-time defense.

Now 6-2 has become 6-5, and Aaron Rodgers and the Perfect Packers are rested and waiting, what are we supposed to think now?

That this time Joe Pisarcik will be playing for the other guys? That this time Matt Dodge will be punting for the other guys?

“This is our playoffs,” Tuck said.

At this rate, Coughlin’s hot seat will soon be reaching sauna proportions. If he remains at a loss to cure finish-itis, then management may reluctantly decide on regime change four years after Super Bowl XLII.

These Giants have vowed they would finish games and finish this season.

So I ask: What has happened to the gritty overachievers who shocked the Dream Team in Philadelphia and rode the fourth-quarter magic in Manning’s right arm to outlast Tom Brady in Foxborough?

What has happened to the defiant, all-for-one-and one-for-all dreamers who somehow overcame one devastating injury after another with a Next Man Up mantra personified by Victor Cruz and Jake Ballard?

Where was the poise in all the noise?

Are the imposters who let the desperate Eagles storm into MetLife Stadium and smack them around from pillar to post with little resistance the real New York Football Giants?

What happened to all that tough talk about smacking the Saints in the mouth?

Because it sure looks like the 2011 Giants are unraveling.

It was 21-3 at the half because the Giants’ fearsome pass rush couldn’t lay a glove on Brees and the back seven couldn’t cover, and so Brees’ second-quarter quarterback rating was a mere 145.

“He does a great job of getting the ball out of his hand quickly, and precisely,” Tuck said.

The Giants closed to within 21-10 early in the third quarter and then the Superdome roof caved in on them.

A remarkable play from Brees: Tuck missed a sack, Brees scrambled right, sidestepped Linval Joseph with a Dancing With the Stars move, finally flipped it to Pierre Thomas for 15 yards and a first down on second-and-15. A screen to Thomas got 24 more and then Deon Grant made Brees look like Michael Vick on his 8-yard TD run that made it 28-10, over and out.

How rattled were the Giants? Steve Weatherford attempted a fake punt even after it was called off. Aaron Ross played a fade to Graham when Graham ran a slant for a 5-yard TD.

Brees, up 14-3, took 34 seconds to cover 88 yards to make it 21-3 before the half.

“We weren’t able to cover ’em,” Coughlin said. “When we don’t get to the passer, we have trouble.”

And then it resembles a track meet. Except this one looked like Rex Ryan chasing Usain Bolt.

Collapse.

Swoon.

Meltdown.

“We just gotta remind ourselves that we’re still a great football team ourselves,” Tuck said, “and we still have everything we want right in front of us, and we gotta take advantage of it. And . . . you know . . .” He managed a chuckle.